Conventional wire strippers generally utilize extremely hard metal blades, such as hardened tool steel which typically have a hardness in the range of C50 to C70 on the Rockwell scale. Such blades are capable of cutting through both the plastic insulation and metal conductor. For this reason, in the fabrication of conventional wire strippers, the blades must be dimensioned to close tolerances so they will penetrate and cut the insulation, yet leave the conductor substantially untouched. To this end, the typical hand wire stripper comprises a cutting blade having therein a number of notches or grooves, each notch being dimensioned for use on a different size wire. Such a device requires the operator to properly select the correct notch size, and then carefully close the stripper around the wire so as to cut and penetrate the insulation without damage to the wire. Damage to the conductor is prevalent with such strippers, since such stripping techniques not only require the operator to carefully select the proper notch, but also requires that close tolerances be maintained in the fabrication of the blades as well as the wires. Where either the wire or the blade notch is out of tolerance, poor stripping or damage to the conductor may result. Inadequate penetration of the insulation may cause an incomplete strip of the insulation, or tearing of the insulation resulting in a non-uniform and ragged edge. Penetration of the blade to a depth of greater than the insulation may result in the cutting, gouging or deformation of the conductor, the damaged area being a prime spot for electrical, mechanical or corrosive types of failure.
U.S. Pat. No. 3,703,840 in attempting to obviate the requirement of exact dimensioning of the blade to conform about the wire, provides a plurality of thin blade-like members mounted on spring arms so that they may flex, and move relative to each other when closed about a wire. The spring means is so tensioned that the blade members will cut and sever the electrical insulation but will flex upon contact with the metal conductor. However, it is specifically noted that the cutter blade must be made of a metal and preferably of relatively hard steel. It was previously thought that materials softer than that of a copper conductor which has a typical hardness in the range of B10 to B75 on a Rockwell scale would have marginal penetration into the insulation making it either impossible to strip such insulation or resulting in an extremely ragged edge at the end of the stripped insulation. In addition, it was heretofore accepted that extremely hard cutting steel or a like material was required to insure a reasonable working life.
It is an object of this invention to provide a wire stripper having blades which will strip insulation yet not damage the conductor even if placed in pressure contact therewith. It is another object of this invention to provide such a deformable blade from a single material, without the requirements of springs or flexing configurations.